How did the policy of massive retaliation prevent the united states from becoming involved in the war?

the policy of massive retaliation refers to doctrine that believe a country should invest the largest portion of its military budget into nuclear.

This policy prevent united states from being involved in the war because all  countries would avoid being involved in war with a country that possess weapon of mass destruction due to the potential economic and environmental catastrophe that the war can cause. They much more likely to agree for compromise to resolve international conflict.

after defeating german forces in north africa allied leaders turned their attention to "italy," since this was the location that made the most geographic sense before invading northern europe via france.